First off I have spent almost ten years in Army Intelligence, I know exactly what I am talking about.
Bottom Line: The DOD Intelligence Oversight program states that (Paraphrased) Intelligence personnel may not intentionally target, collect, retain, and disseminate information on U.S. persons CONUS or OCONUS. Information pertaining to U.S. persons posing a threat to DoD personnel, resources or activities, is criminal information and falls under the purview of law enforcement and security. The key word here is intelligence personnel. The argument that "oh, those pysops guys spied on senators" holds no water, army pysops falls under special forces, not MI.
In response to Chris, the US military is not prohibited from conducting operations in the US, the US Military, when under federal control, is prohibited from enforcing US laws by Posse Comitatus. This is why the Coast Guard is not legally considered a military force and falls under DHS and not DOD.

"These reports and others show that that (sic) craigslist's imagined utopia, where every Adult Services advertisement is harmless until proven otherwise, is a fallacy"
Yes!!! it is non-sense to assume anyone posting an add on craigslist is innocent until proven guilty, heck it's downright un-American to presume that something is legal before it is proven otherwise.